Discussion
Several elements of information can be derived from our study. First, NPPV is feasible in acute respiratory failure, when only the possibility of lowering an increased PaC02 is considered; however, in some patients, particularly the obstructive group, intubation appears to be ultimately unavoidable. It is unlikely that this technique will be considered as a way to buy time before intubation in such patients; endotracheal intubation is widely available, safe, and very often technically easy, whereas NPPV seems to require specific technical capacities and active cooperation by the patient. This latter condition is far from present in all decompensated, severely hypercapnic patients with COPD. Secondly, acute NPPV seems to be clearly easier in patients with restrictive than in patients with obstructive respiratory diseases. Thirdly, in any type of patient, and even if acute NPPV proves successful in avoiding intubation, the technique is very time-consuming for the health-care providers.The fact that NPPV is easier and more successful in patients with restrictive than in patients with obstructive respiratory failure is not really a surprise. First, some groups having treated patients with COPD who are in acute respiratory failure with NPPV have already shown that some of them had to be ultimately intubated because of failure of NPPV.